Multistage blower



June 12, 192s. 1,672,986

G. w. MCKEE MULT I STAGE BLOWER Filed April 17. 1922 2 sheets sheet l June 12, 1928. 1,672,986

G. W M KEE MULT I STAGE BLOWER,

F1 1922 2 Sheets-Sheet 3 Patented June 12, 1928.

UNITED .STATES GARNET W. mom, 0] ROCKFORD, ILLINOIS.

MULTISTAGE nLownn.

Application filed April 17, 1922. .Serial 110.653,!)09.

This invention pertains generally to blowers adapted to move air or other fluids under pressure, and relates more specifically to high pressure blowers which are adapted to produce a higher pressure than the ordinary single stage blower.

One of the primary purposes of my present invention is to provide a blower of the character indicated which will be highly eflicient in use, and which, because of its simplicity of construction, can be produced at relatively low cost.

Another purpose of the invention is to provide a blower which can be readily taken apart for purposes of inspection or repairs, and which, when assembled, will occu y only a small amount of space and can be s ipped and sold together with its motor to which it is directly connected, as a unit.

On the accompanying drawings I have illustrated a preferred embodiment of my invention, and referring thereto-- Fig. 1 is a side elevation partially in section of a blower embodying my invention;

Fig. 2 is a face view with the outer casing removed, taken on the line 22 of Fig. 1;

Fig. 3 is a face view of one of the partition wall plates, showing the arrangement of the passages; and

Fig. 4 is a face view of the outer plate of this partition wall.

The blower embodying my invention may be driven from any suitable source of power. It is preferably directly connected with an electric motor indicated on the drawing by reference character 5, which is supported upon a suitable base 6. The blower casing is also carried by the base 6, and as will be apparent from Fig. 2, comprises an inner plate 7 which has formed integrally therewith or attached thereto, as shown, a hollow ring 8 terminating in a tangentially disposed discharge pipe 9. The casing is closed at the front side b a plate 11 secured by lag bolts 12 or other eta'chable fastenin means to the ring 8. The casing is divide into two compartments 13 andlt respectively by a central partition wall which comprises an inner plate or member 15 and an outer plate 16.

The inner plate 15 is secured to the ring member 8 by a pass through its peripheral edge into the ring member 8, and is provided on. its face opposed to the plate 16 with a plurality of plurality of screws 17 whichblocks, or preferably ribs 18, formed integrally with the plate and so shaped and relat1vely disposed as to provide between adjacent ribs, passages 19, substantially s iral in general contour and adapted to establish communication between the perimeter of the compartment 13 and the central ortion of the compartment 14, the plate 15 b vided with a central 0 ening 21 through which the air delivered lay the passages 19 is discharged into the compartment 14. The outer plate 16 which forms the outer wall for these passages is secured to the plate 15 by a plurality of bolts 22. To facilitate the deflection of the air issuing from the passages 19 into the compartment 14, the plate 16 has itscentral portion slightly olfset as indicated by reference character 23. The blocks 18 are so disposed on the plate 15 as to have a large portion of their outer edges parallel with the circumference oithe plate 15. At the points radially outside of these parallel peripheral ortions "of the blocks 18 the space define between those blocks and the curved peripheral portion of the plate 11 will be uniform for as much of the circumferential distance as is equal to the said parallel portion of the block 18. As a result air being forced centrifugally from the outer, or primary fan compartment will be confined within a non-expandin space for a distance and then is permitte to move into the channels 19 between these blocks. The channels 19, by reason of the shape of the blocks, taper reducingly to their delivery ends. In this'manner they tend to further compress the air coming from the primary fan compartment before it is delivered tangentially by the passages 19 into the ath of the rotating fan blades in the secon ary compartment.

It will be noted, that, as in Fig. 1, the fan blades and the compartments in which they rotate are tapered graduall and decreasingly toward their peripheral portions. COIISQQKGIltIy, the air is being moved throng the multi-sta e blower throu h passages and chambers wdiich are gradua ly decreasing in their cross section.

In order that the air from the rimary compartment may be delivered e ciently with a minimum of eddy currents the peripheral portions of the plate 11 are concave, as. illustrated in Fig. 1. The maximum diameter of the ooncaved interior surface of the deflecting chamber which regiseing proters with the outer ends of the passages 19 and the primary fan compartment is located mid way between the passages 19 and the primar fan compartment. This shape of the de ecting chamber prevents accumulations-of the eddy currents which would retend the passage of air currents therethrough and would greatly reduce the general efficiency of the blower. This curvature, having its maximum diameter located as illustrated, yields the maximum deflecting effect desired with the minimum of frictional resistance and, as a consequence, the air delivered centrifugally by the primary fan compartment is deflected into the passages 19 with the smallest possible frictional losses. 1

A centrifu a1 fan blower comprising a plurality of b ades 24 carried by a hub 25 is mounted upon the motor shaft within the compartment 14 and locked against displacement on the shaft by a lock nut 27. A plate 28 closes the central openin .in the casing plate 7, and to prevent air which may escape under pressure around the shaft 26 from blowing the oil out of the motor, a ring 29 forming a radially projecting flange is mounted on the shaft outside the plate.

Within the compartment 13 a similar fan blower, comprising a series of blades 31 carried by a hub 32 which is locked on the shaft by a lock nut 33, is mounted. The two blowers are preferably of the same size and capacity and air enters the compartment 13 through an'intake opening 34 provided centrally of the plate 11.

In assembhng the machine, the hub 25 is first locked in position on the shaft, the partition wall, comprising the plates 15 and 16, is then secured in position, the hub 32 of the other blower is then locked to the shaft, and lastly, the plate 11 is fastened over the front of the casing.

In operation, the fans being rotated at high speed by the motor, air is drawn into the first compartment 13 through the inlet openin 34, and is centrifugally impelled by the action of the fan to the perimeter of the compartment 13 where it enters the opposed inlet ends of the passages 19, by which it is conducted without the establishment of eddies or back currents to the opening 21 leading into the compartment 14, where its pressure is still further built up by the action of the fan in this compartment which eventually causes the air to be discharged under considerable pressure through the delivery pipe 9.

y lnvention is simple in construction, economical to manufacture, eas to assemble and dismantle, and is highly ecient in operation. The shape of the passages 19 is such that the air is conducted from the first to the second chamber without loss of pressure or volume, which would result if eddies or back currents were set u and the air, therefore, flows smoothly an steadily from the first fan to the second where the pressure imposed by the first fan is materially increased by the action of the second fan. My invention, therefore, provides a multi-stage blower possessing man practical advantages, and while a pre erred form thereof has been shown and described, it should be manifest that the structural details may be varied within wide limits without departing from the essence of the invention as defined in the following claim.

I claim:

A multi-stage blower comprising a primary fan compartment, a secondary fan compartment, a rotatable fan in each compartment, each fan and each compartment being gradually tapered decreasingly toward its perimeter, a partition between said compartments comprising a primary wall. a secondary wall having a central opening. and blocks disposed between said walls defining with the walls a plurality of spiral passages adapted for delivering fluids tangentially through said central opening and into the central portion of the secondar compartment, the cross sectional area. of the passages being gradually decreased toward their central openin substantial portions of the peripheral e l ges of said blocks being arcs of a common circle, an annular deflecting chamber disposed peripherally outside of the primary fan compartment and said passages for connecting said compartment and passages, the portion of the chamber overlying the primary compartment having diameters less than the maximum diameter of the chamber, and means for conducting fluids directly and tangentially from the periphery of the secondary com artment.

GARN T W. MoKEE. 

